Brillouin scattering studies of ferroelectric triglycine selenate sound velocity versus uniaxial pressure at T similar to T-C

Brillouin spectroscopy was used to study the influence of uniaxial pressure sigma(b), applied along the b polar direction, on transverse polarization fluctuations in ferroelectric TGSe single crystals. The experiments were pe rformed with sigma(b) varying from 0 to 8 MPa at temperatures from 785 to 3 05 K. It was found that increasing pressure shifts the phase transition tem perature towards lower values, producing a slowing down the relaxation proc ess at T similar to T-C. It was also possible to induce the ferroelectric t o paraelectric phase transition at a constant temperature by varying the un iaxial pressure. (C) 1999 Elsevier Science B.V. All rights reserved.